Fluid operated pump assembly with tandem engines

ABSTRACT

A fluid operated, tandem engine, pump assembly for oil wells comprising upper and lower fluid operated, reciprocating engines and a reciprocating pump arranged in tandem with the pump below the lower engine. Two passage means respectively interconnect the upper ends and the lower ends of the two engine cylinders. The two passage means include large-area vertical passages radially outwardly of the upper engine cylinder, but within the outside diameter of the pump assembly. An engine valve means incorporated in the upper engine alternately connects the two passage means to a source of operating fluid under pressure and a point of disposal for spent operating fluid.

United States Patent 1151 3,653,786 McArthur et al. 1 Apr. 4, 1972 s41 FLUID OPERATED PUMP ASSEMBLY 2,726,605 12/1955 Tebbetts ..91/411 A x WITH TANDEM E I 2,576,924 12/1951 Coberly ..417/404 [72] Inventors: Ralph F McArthur, Huntington Park; Melle F. Geurts, Los Angeles, both of Calif.

[73] Assignee: Kobe, lnc., Huntington Park, Calif.

[22] Filed: July 6, 1970 [21] App]. No.: 52,382

[52] 0.8. CI ..4l7/404, 91/411 [51] Int. Cl ..F04b 17/00, F04b 35/00, Fl5b 11/00, Fl5b 13/00 [58] Field of Search ..4l7/399, 404; 91/411 A [56] References Cited UNITED STATES PATENTS 2,245,501 6/1941 Richardson ..91/41l A Primary Examiner-Robert M. Walker Attorney-Harris, Kiech, Russell & Kern [57] ABSTRACT A fluid operated, tandem engine, pump assembly for oil wells comprising upper and lower fluid operated, reciprocating engines and a reciprocating pump arranged in tandem with the pump below the lower engine. Two passage means respectively interconnect the upper ends and the lower ends of the two engine cylinders. The two passage means include large-area vertical passages radially outwardly of the upper engine cylinder, but within the outside diameter of the pump assembly. An engine valve means incorporated in the upper engine alternately connects the two passage means to a source of operating fluid under pressure and a point of disposal for spent operating fluid.

3 Claims, 7 Drawing Figures FLUID OPERATED PUMP ASSEMBLY WITH TANDEM ENGINES BACKGROUND OF THE INVENTION The present invention relates in general to fluid operated, reciprocating pumps and, more particularly, to pumps of this type for wells, especially oil wells.

More specifically, the invention relates to a reciprocating fluid operated pump assembly having tandem engines to provide more power for driving the piston of the pump of the assembly. This construction provides increased pumping capacity for wells producing large quantities of fluid, wells wherein flow resistances are high because of their depths, wells producing low gravity oil creating high flow resistances, and the like.

Still more specifically, the present invention contemplates a fluid operated, tandem engine, pump assembly which includes: upper and lower fluid operated engines and a pump arranged in tandem with the pump below the lower engine; upper and lower engine pistons respectively reciprocable in upper and lower engine cylinders forming parts of the upper and lower engines; a pump piston reciprocable in a pump cylinder forming part of the pump; rods interconnecting the upper and lower engine pistons and the pump piston; two passage means one interconnecting the upper ends of the upper and lower engine cylinders and the other interconnecting the lower ends thereof; and engine valve means forming part of one of the engines, preferably the upper engine, for alternately connecting the two passage means to a source of operating fluid under pressure and a point ofdisposal for spent operating fluid.

OBJECTS OF INVENTION With the foregoing background in mind, the primary object of the invention is to provide two large-area passage means respectively interconnecting the upper ends and the lower ends of the upper and lower engine cylinders, thereby minimizing the resistances to flow of operating fluid under pressure and spent operating fluid.

More particularly, an important object of the invention is to provide'a pump assembly wherein the two passage means under consideration include relatively large vertical passages located radially outwardly of and alongside the upper engine cylinder. A related object is to provide a construction wherein the vertical passage include annular passages encompassing the upper engine cylinder.

Another object of the invention is to provide a pump assembly which includes an upper rod extending upwardly from the engine piston to control the engine valve means and having its upper end exposed to the source of operating fluid under pressure, a lower rod extending downwardly from the pump piston, a balance tube enclosing the lower end of the lower rod, and passage means through all of the rods and pistons for maintaining operating fluid pressure in the balance tube so as to apply such pressure to the lower end of the lower rod to balance the rod area.

Another important object of the invention is to provide a tandem engine pump assembly which is basically a composite of two prior fluid operated pumps so that existing parts may be used for much of the pump assembly of the present invention to reduce manufacturing costs. For example, the pump assembly of the present invention may combine the fluid operated pump of U.S. Pat. No. 2,311,157, issued Feb. 16, 1943 to Clarence J. Coberly, and the fluid operated pump of U.S. Pat. No. 3,078,804, issued Feb. 26, 1963 to Ralph F. McArthur and Matthew R. Mecusker.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident to those skilled in the fluid operated oil well pump art in the light of this disclosure, may be achieved with the exemplary embodiment of the invention described in detail hereinafter and illustrated in the accompanying drawings.

DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a vertical sectional view of a bottom hole assembly containing a fluid operated, tandem engine, pump assembly which embodies the invention, FIG. 1 being taken substantially along the irregular arrowed line 1--l of FIG. 6;

FIG. 2 is a downward continuation of FIG. 1;

FIG. 3 is a downward continuation of FIG. 2;

FIG. 4 is a downward continuation of FIG. 3;

FIG. 5 is a downward continuation of FIG. 4;

FIG. 6 is a horizontal sectional view taken as indicated by the arrowed line 6-6 of FIG. 1; and

FIG. 7 is a horizontal sectional view taken as indicated by the arrowed line 77 of FIG. 2.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT OF INVENTION Referring to the drawings, designated generally therein by the numeral 10 is a fluid operated oil well pump system of the closed type, i.e., of the type in which spent power oil or other operating fluid is returned to the surface independently of the production fluid from the well. (However, the invention is not limited to this type). The pump system 10 includes a bottom hole assembly 12 adapted to be suspended in an oil well, not shown, by supply, return and production tubings 14, 16 and 18. The bottom hole assembly 12 is adapted to receive therein a fluid operated, tandem engine, pump assembly 20 of the invention. As will be understood, the pump assembly 20 is operable by operating fluid under pressure delivered thereto through the supply tubing 14, spent operating fluid being conveyed to the surface through the return tubing 16, while production fluid from the well is conveyed to the surface through the production tubing 18. The pump assembly 20 is of the type which is capable of being circulated into and out of the well through the supply tubing l4-hydraulically. As is well known, the pump assembly 20 is circulated in by introducing operating fluid under pressure into the supply tubing 14 thereabove. When it is desired to circulate the pump assembly 20 out of the well through the supply tubing 14, operating fluid under pressure is introduced beneath the pump assembly through the return tubing 16.

The pump assembly 20 of the invention, as hereinbefore indicated, is composed largely of conventional components from the aforementioned U.S, Pat. Nos. 2,31 1,157 and 3,078,804. Similarly, the bottom hole assembly 12 is largely conventional, differing only in the modifications necessary to accommodate the tandem engine pump assembly 20 of the invention. Accordingly, the bottom hole assembly 12 and the pump assembly 20 will be described only generally herein insofar as they are conventional, and only the modifications involved in the present invention will be considered in detail.

Considering the bottom hole assembly 12 generally, it includes upper, middle and lower bodies 22, 24 and 26, respectively shown in FIGS. 1, 3 and 5, which are interconnected by upper and lower tubes 28 and 30 aligned with the supply tubing 14 and receiving the pump assembly 20 therein. The lower end of the pump assembly 20 is seated on a standing valve assembly 32, FIG. 5, which communicates with the well to admit well fluid into the lower end of the pump assembly. As is conventional, the standing valve assembly 32 is seated in the lower body 26.

The lower end of the supply tubing 14 is connected to the upper body 22 and supplies operating fluid under pressure to an operating fluid inlet 34 of the pump assembly 20 through a packer mandrel 35 at the upper end thereof. The upper body 22 is provided therein with a passage, designated generally by the numeral 36 in FIG. 2, which conveys operating fluid under pressure downwardly to a tubing means 38 connected at its lower end, FIG. 3, to a passage 40 in the middle body 24. A port 42 connects the passage 40 to the interior of the middle body 24 to apply operating fluid under pressure to seal assemblies 44 on the pump assembly 20 in the manner disclosed in the aforementioned U.S. Pat. No. 3,078,804. (The pump assembly is provided with similar pressurized seal assemblies 46 and 47 within the upper and lower bodies 22 and 26, which seal assemblies need not be described in detail since they are also similar to these disclosed in U.S. Pat. No. 3,078,804.)

The lower end of the return tubing 16 is connected to the upper body 22 in communication with a passage 48 which, in turn, communicates with a spent operating fluid outlet 50 of the pump assembly 20. The passage 48 also communicates with a passage 52 leading to a tubing means 54 which extends downwardly through the middle body 24 and is connected at its lower end to the lower body 30, FIG. 5, in communication with a passage 56 leading to the lower end of the pump assembly 20 just above the standing valve assembly 32. With this construction, when it is desired to circulate the pump assembly 20 out of the well through the supply tubing 14, operating fluid under pressure is delivered to the lower end of the pump assembly 20 through the return tubing 16, the passages 48 and 52, the tubing means 54 and the passage 56 to displace the pump assembly upwardly in a manner well known Y in the art.

The production tubing 18 extends downwardly through the upper body 22 and is connected at its lower end to the middle body 24, FIG. 3, in communication with a production fluid passage 60 through the middle body. The passage 60 communicates through a port 62 with an upper production fluid outlet 64 of the pump assembly 20. The lower end of the passage 60 communicates with a tubing means 66 which extends downwardly to and is connected at its lower end to the lower body 26, FIG. 5, in communication with a production fluid passage 68 in the lower body. A port 70 connects the passage 68 and a lower production fluid outlet 72 of the pump assembly. 20.

Turning now to a general consideration of the pump assembly 20, it includes upper and lower fluid operated engines 82 and 84 and a pump 86 arranged in tandem with the pump below the lower engine. The upper engine 82 includes an engine valve or valve means 88 which controls both engines 82 and 84 in a manner to be described. The upper engine 82 and its engine valve 88 are similar to the engine and engine valve combination disclosed in U.S. Pat. No. 2,311,157. The lower engine 84 and the pump 86 are similar to the engine and pump combination disclosed in U.S. Pat. No. 3,078,804. In other words, the pump assembly 20 comprises basically the combination of the engine and engine valve of U.S. Pat. No. 2,311,157 with the engine and pump of U.S. Pat. No. 3,078,804, with modifications to enable the engine valve 88 of the upper engine 82 to control both the upper engine and the lower engine 84. Consequently, the engines 82 and 84, the pump 86 and the engine valve 88 will be described only generally herein, reference hereby being made to the patents mentioned for more complete disclosures of these components. The present invention resides in the manner in which the upper and lower engine 82 and 84 are connected to enable the engine valve 88 to control both of them, and this, of course, will be described in detail herein.

Continuing to consider the upper and lower engines 82 and 84, the pump 86 and the engine valve 88 generally, the upper and lower engines respectively include upper and lower engine cylinders 90 and 92 respectively containing upper and lower engine pistons 94 and 96. The pump 86, which is a double acting pump, includes a pump cylinder 98 containing a pump piston 100. lnterconnecting the engine pistons 94 and 96 is an upper intermediate rod 102 and interconnecting the lower engine piston 96 and the pump piston 100 is a lower intermediate rod 104. Carried by and extending upwardly from the upper engine piston 94 through the engine valve 88 is an upper rod 106 which controls the engine valve in the manner set forth in U.S.Pat.No. 2,311,157.

The upper end of the upper rod 106 is constantly exposed to the operating fluid pressure in the operating fluid inlet 34. To balance'this pressure acting on the rod area, the operating fluid pressure is also applied in the upward direction on an equal area. Considering how this is accomplished, a lower rod 108 is carried by and extends downwardly from the pump piston into a balance tube 110 closed at its lower end. Passage means 1 12 through the various pistons 94, 96 and 100 and the various rods 102, 104, 106 and 108 interconnect the operating fluid inlet 34 and the balance tube 110 to apply the operating fluid pressure to equal areas at the upper end of the upper rod 106 and the lower end of the lower rod 108.

As previously mentioned, the engine valve 88 controls both the upper engine 82 and the lower engine 84. More particularly, the body or housing of the pump assembly 20 is provided therein with a passage means 116 interconnecting the upper ends of the upper and lower engine cylinders 90 and 92 and a passage means 1 18 interconnecting the lower ends thereof. As shown in FIG. 1, the two passage means 116 and 118 communicate with the engine valve 88 at their upper ends and the engine valve alternately connects the two passage means to the supply tubing 14 and the return tubing 16, in essentially the same manner as the engine valve of U.S. Pat. No. 2,311,157 alternately connects the upper and lower ends of the engine cylinder disclosed therein to high and low pressure.

An important feature of the present invention is that the passage means 116 and 118 comprise large-area passages, in-

' cluding annular passages, located radially outwardly of and alongside the upper engine cylinder 90, but within the outside diameter of the pump assembly 20, to minimize flow restrictions between the engine valve 88 and the lower engine cylinder 92. Consequently, the lower engine 84 is capable of maximum power output.

Considering in more detail the passage means 1 16 interconnecting the upper ends of the engine cylinders 90 and 92, it includes an annulus or annular passage 120 which encircles and extends the full length of the upper engine cylinder 90, as shown in FIGS. 1 and 2. At its lower end, the annulus 120 communicates with vertical passages 122, FIGS. 2 and 7, which communicate directly with the upper end of the lower engine cylinder 92. The upper end of the passage means 116 communicates with the upper end of the upper engine cylinder 90 through a passage 124.

The passage means 118 includes an annulus or annular passage 126 between the body of the pump assembly 20 and the tube 28 interconnecting the upper and middle bodies 22 and 24. As shown in FIG. 1 and 2, the annulus 126 extends downwardly from the region of the engine valve 88 alongside the upper engine cylinder 90, which it encircles, 'and communicates with passages 128 which connect it to the lower end of the upper engine cylinder 90, as shown in FIGS. 2 and 7. From the level of FIG. 7, the annulus 126 extends downwardly alongside and encircles the lowe engine cylinder 92. The lower end of the annulus 126 communicates with the lower end of the engine cylinder 92 through ports 130, passages 132 and ports 134. Thus, the passage means 118 interconnects the lower ends of the upper and lower engine cylinders 90 and 92 and connects them to the engine valve 88.

As will be apparent, the annular passages 120 and 126 and the multiple passages 122 and 128 provide the passage means 116 and 118 with relatively large areas to minimize flow re sistances therethrough. Consequently, as the engine valve 88 alternately connects the two passage means 116 and 118 to the supply tubing 14 and the return tubing 16 to impart reciprocatory motion to the upper and lower engine pistons 94 and 96, pressure drops throughout the engines 82 and 84 are minimized to obtain the maximum possible power output from both engines, and particularly the lower engine 84.

As previously indicated, the pump 86 is substantially identical to the pump portion of the pump assembly disclosed in U.S. Pat. No. 3,078,804. Consequently, the pump 86 will be described only briefly herein.

The pump 86 is a double acting pump, being equipped at the upper and lower ends of the pump cylinder 98 with upper and lower inlet valves 136 and 138, respectively shown in FIGS. 3 and 4, and upper and lower outlet valves and 142, also respectively shown in FIGS. 3 and 4. (Only one of each of the inlet valves 136 and 138 and one of each of the outlet valves 140 and 142 are shown in the drawings.) The inlet valves 136 and 138 respectively admit well fluid into the upper and lower ends of the pump cylinder 98 through inlet ports 144 and 146, respectively shown in FIGS. 3 and 4. These inlet ports communicate with an annulus 148 between the body of 5 the pump 86 and the lower tube 30 of the bottom hole assembly 12. The lower end of the annulus 148 receives well fluid through an axial passage 150, FIG. 5, communicating at its lower end with the well through the standing valve assembly 32.

As shown in FIG. 3, the upper outlet valves 140 communicate with the production fluid port 62 through a passage means 152. The lower outlet valves 142 communicate with a passage means 154, FIGS. 4 and 5, leading to the production fluid port 70. As previously explained, the production fluid ports 62 and 70 both communicate with the production tubing 18 leading to the surface.

Although an exemplary embodiment of the invention has been disclosed for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims appearing hereinafter.

We claim:

1. In a fluid operated, tandem engine, pump assembly, the combination of:

a. upper and lower fluid operated engines and a pump arranged in tandem with said lower engine between said upper engine and said pump;

b. said upper and lower engines respectively including upper and lower engine cylinders containing upper and lower engine pistons;

c. said pump including a pump cylinder containing a pump piston;

d. rods interconnecting said upper and lower engine pistons and said pump piston;

e. two passage means one interconnecting the upper ends of said upper and lower engine cylinders and the other interconnecting the lower ends of said upper and lower engine cylinders;

f. said passage means including vertical passages located radially outwardly of and alongside said upper engine cylinder;

g. engine valve means for alternately connecting said passage means to a source of operating fluid under pressure and a point of disposal for spent operating fluid;

h. an upper rod carried by and extending upwardly from said upper engine piston and having its upper end exposed to the source of operating fluid under pressure;

i. a lower rod carried by and extending downwardly from said pump piston;

j. a balance tube enclosing the lower end of said lower rod;

and

k. passage means through all of said rods and pistons for conducting operating fluid under pressure to said balance tube so as to apply the operating fluid pressure to the lower end of said lower rod, and thereby hydraulically balance the rod areas, and hence the entire piston and rod system.

2. A fluid operated, tandem engine, pump assembly as set forth in claim 1 wherein said engine valve means is incorporated in said upper engine.

3. A fluid operated, tandem engine, pump assembly according to claim 1 wherein portions of said vertical passages are annular passages.

mg UNITED. STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 3.653.786 I Dated Ap ril r, 1972 Inventor) RALPH F. McARTHUR and MELLE F. GEUR'I'S It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 47, "passage" (first occurrance) should be --passages--;

Column 1, line 5l,'after "the" (first occurrence) insert Column 2, line 69, "Fi 2" should'be "Fig. 1--;

Column 4, line 50, "lowe" should be "lower- Signed and sealed this 10th day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. In a fluid operated, tandem engine, pump assembly, the combination of: a. upper and lower fluid operated engines and a pump arranged in tandem with said lower engine between said upper engine and said pump; b. said upper and lower engines respectively including upper and lower engine cylinders containing upper and lower engine pistons; c. said pump including a pump cylinder containing a pump piston; d. rods interconnecting said upper and lower engine pistons and said pump piston; e. two passage means one interconnecting the upper ends of said upper and lower engine cylinders and the other interconnecting the lower ends of said upper and lower engine cylinders; f. said passage means including vertical passages located radially outwardly of and alongside said upper engine cylinder; g. engine valve means for alternately connecting said passage means to a source of operating fluid under pressure and a point of disposal for spent operating fluid; h. an upper rod carrIed by and extending upwardly from said upper engine piston and having its upper end exposed to the source of operating fluid under pressure; i. a lower rod carried by and extending downwardly from said pump piston; j. a balance tube enclosing the lower end of said lower rod; and k. passage means through all of said rods and pistons for conducting operating fluid under pressure to said balance tube so as to apply the operating fluid pressure to the lower end of said lower rod, and thereby hydraulically balance the rod areas, and hence the entire piston and rod system.
 2. A fluid operated, tandem engine, pump assembly as set forth in claim 1 wherein said engine valve means is incorporated in said upper engine.
 3. A fluid operated, tandem engine, pump assembly according to claim 1 wherein portions of said vertical passages are annular passages. 